The present invention relates to targets which are useful for various applications such as surveying, sighting and orienting.
Laser light sources have been increasingly used in surveying and various optical sighting and orienting systems. These typically involve a high power laser projecting light upon a distant target and require certain protective measures to avoid damage to the human eye. Moreover, the laser beam expands in diameter with distance. Optical prisms, mirrors and the like have been used as targets, but the larger the light spot, the greater the error. Multiple prisms and mirrors are used in this case.
The object of the present invention is to provide an improved surveying target which does not require the use of high powered lasers and which allows work in any light level, is impervious to thermal waves, functions in fog, rain, haze and smoke, extends the range of standard refractional surveying instruments up to ten times, uses low power, can be retrofitted to current target systems and be operated by remote control. A further object of the invention is to provide a surveying system using the optical instrument disclosed in my above-identified application Ser. No. 064,419 and incorporated herein by reference.
A high intensity gas discharge flash lamp or tube (filled with xenon or krypton gases) is contained in a light absorbing enclosure and oriented to an open side of he enclosure. The enclosure may be of the same physical dimensions and have the same mounting fitments as those used for prism type targets so that they can be retrofitted to and adapted to incorporate this invention. The light absorbing portion of the enclosure keeps the light beams from the discharge tube from expanding and spreading thereby enhancing accuracy of surveying measurements using this invention, particularly at the longer measuring distances made possible thereby. A power supply is controlled to charge a standard discharge capacitor very fast and a high voltage coil steps the voltage up to 700 volts or more. A voltage regulator on the power supply assures a constant pulse discharge rate (which preferably is about 2 per second) when the battery voltage gets low. In addition, a remote radio control is provided to thereby permit close control by the surveyor and make possible reduction in surveying man power.
Thus, the present invention provides an improved surveying target which results in:
1. Allows work at any light level, including night work,
2. Impervious to thermal waves,
3. Functions on fog, rain, haze and smoke,
4. Extends the range of standard refractional surveying instruments up to 10 times, meaning less drops and therefor less cumulative error,
5. Low power consumption,
6. Retrofit into all standard surveying target systems,
7. Will work with the retrolaser surveying system
8. Will give horizontal or vertical reference,
9. Radio remote control available with automatic control number of flashes, and
10. Automatic, no warm-up operation.
The optical instrument disclosed in my above-identified applications uses a lower power collimated point light source surrounded by an optical void and alignable along a predetermined viewing axis. When one eye of the observer is aligned with the point light source and the other eye is viewing a scene, the light spot is optically fused into the scene and where the viewing axis is precisely aligned with the point in the scene where the light spot appears. This provides a surveying system with the following advantages:
(1) greater accuracy, PA0 (2) impervious to : PA0 (3) minimal power requirements, PA0 (4) range limited only by line of sight, PA0 (5) simpler to use, and PA0 (6) minimal adjustments previous to use.
(a) condensation, PA1 (b) rising thermal waves, PA1 (c) full functions under various light conditions,